In "Roma," Mexican writer/director Alfonso Cuarón uses a large canvas to tell the story of lives that some might think small.

A personal epic set in Mexico City in the early 1970s, it centers on a young indigenous woman who works as a maid for a middle-class white family that's falling apart. Cuarón uses one household on one street to open up a world, working on a panoramic scale often reserved for war stories, but with the sensibility of a personal diarist. It's an expansive, emotional portrait of life buffeted by violent forces.

Cuarón's filmmaking style has grown more exhilarating as the expressive realism of his breakout movie, "Y Tu Mamá También," has been channeled into the restrained ostentation of his fantasies "Children of Men" and "Gravity." In "Roma" he has further refined his style by marshaling various narrative strategies, including cinematic spectacle. Many directors use spectacle to convey larger-than-life events. Here, Cuarón uses intimacy and monumentality to express the depths of ordinary life.

The movie shares its name with a neighborhood in Mexico City where families live behind locked gates, and where maids, cooks and drivers busily keep homes running. In one such house, Cleo (Yalitza Aparicio) lives with and works for a multigenerational brood that scarcely seems capable of doing anything without her.

Much of the movie takes place inside the house, which is flanked by a gated, open-roofed passage filled with bicycles, plants, caged birds and an exuberant, underloved dog named Borras. Cleo and her friend Adela (Nancy García Garcia), the family cook, live at the end of the corridor in a tiny, cramped upstairs room. The women are from the same village in the southern state of Oaxaca and fluidly slip between Spanish and Mixtec, their native tongue, as they share gossip and sober news from home.

A series of catastrophes slowly upends the stability of this world. In one of the most astonishing sequences, Cleo and the family's grandmother, Señora Teresa (Verónica García), watch through the window of a furniture showroom as a student demonstration turns into a riot. Cuarón doesn't identify the incident — known as the Corpus Christi Massacre of 1971 — but fills in that day with visceral, harrowing flashes of chaotic violence, including a pietà-like image of a woman crying for help while cradling a dying man.

In addition to writing and directing, Cuarón shot the movie himself, and his work is astonishing. He filmed in black-and-white, large-format digital, creating images that have extraordinary clarity, detail and tonality.

Cuarón is conversant in Hollywood storytelling, but here he also makes expressive use of the kind of tableau staging — arranging people in the frame — that is more familiar from art cinema. By letting a scene play out without much editing, he lets us see how each of these characters inhabits these specific spaces.

Although the film is autobiographical, Cuarón doesn't explicitly announce it as such. The family's four children — a girl and three boys, one presumably based on the filmmaker — tend to blur into a cacophonous, charming little mob and you catch their names only in passing.

Cuarón's authorial voice becomes progressively more conspicuous through his visual choices, his staging and camerawork. Much happens, but in fragments that slide together as the family and larger sociopolitical forces come into focus. Cuarón folds just enough exposition into ordinary-sounding conversations to keep you tethered and doesn't step on the story by overcutting it.

The film is dedicated to "Libo," Liboria Rodríguez, the woman who raised him in a house like the one in the movie, where every so often you can see a jet passing overhead, a vision that points to a distant, peripatetic future, even as it suggests that Cuarón never left this place and its love.